FIG. 5 shows a light source 1 which is generally used for a liquid crystal display apparatus. Both ends of the light source 1 are protected by covers 2 made of rubber. The covers also function as an attaching section. A lead wire 3 is provided through each cover 2. Each end of the lead wires 3 is provided with a harness 4.
FIGS. 6 through 8 show respective examples where the liquid crystal display apparatus is furnished with the light source 1. Each example is of a side-lighting type wherein the light source 1 is disposed so as to be integrally mounted in the vicinity of an end of a light guiding plate 5. A sheetlike reflector 6 is provided around a light source 1 according to the example of FIG. 6. A light guiding plate 5 and a light source 1 are supported by a chassis 7 made of plastic according to the example of FIG. 7. A protecting member 8 made of plastic is screwed into the chassis 7 so as to cover the light source 1. A light guiding plate 5 and a light source 1 are supported so as to be put between a lower chassis 9 made of plastic and an upper vessel 10 made of metal made according to the example of FIG. 8.
However, the above-mentioned conventional liquid crystal display apparatus has the following problems:
1 It is troublesome to change the light source 1. This derives from a structural problem where the light source 1 is integrally provided with either a main body of the liquid crystal display apparatus or the light guiding plate 5. Note that it is necessary to change the light source 1 in order to avoid a drop in brightness, since a cold cathode ray tube or a thermal cathode ray tube which are used for the light source 1 have a predetermined lifetime;
2 The light source 1 required to be handled with great care. This is because the light source 1 has a fine glass tube which should be transported and handled without any cover until it is incorporated into the liquid crystal display apparatus;
3 It is troublesome to wire the light source 1 for electricity. This is because it is required to pass the harness 4 through a leading hole (not shown) of a main body of the liquid crystal display apparatus and to fix the lead wire 3;
4 It is hard to standardize and commonly use the light source 1. This is because the tube length of the light source 1, the length of the lead wire 3 and other dimensions are generally designed in accordance with a kind of the liquid crystal display apparatus which is furnished with the light source 1 inside thereof;
5 The structure of the respective members 6 to 10 which are disposed around the light source 1 is complicated. This is because each of the members 6 to 10 has (1) structure where the light from the light source 1 is converged onto the light guiding plate 5 in order to increase the brightness of back light and (2) the structure where the light source 1 is integrally provided with either the main body of the liquid crystal display apparatus or the light guiding plate 5; and
6 The heat of the light source 1 is conducted to the liquid crystal display plate, thereby sometimes inducing a so-called voiding phenomenon. This is because in the case where the light source 1 is integrally provided with either the main body of the liquid crystal display apparatus or the light guiding plate 5, it is hard to thermally insulate the liquid crystal display plate from the light source 1, thereby resulting in that a temperature characteristic of the liquid crystal display plate is badly affected by the heat of the light source 1.